Energy pump voltage regulator

ABSTRACT

A circuit for increasing and regulating the voltage appearing at the input terminals of a power supply. A plurality of cascaded stages are provided. Each stage comprises: an inductive energy storage device; a switching device; a control device; and a discharge path. Control signals, having a selectable sequential time relation therebetween, are provided to the stages so that energy discharged from adjacent stages is caused to overlap in time. The amount of overlap is adjustable and is dependent upon the sequential time relation between the control signals which is selected.

ilnited States Patent 1 Lachocki 51 May 29, 1973 [54] ENERGY PUMPVOLTAGE REGULATOR Eugene Lachocki, Turnersville, NJ. 08012 Assignee: RCACorporation, New York, N.Y.

Filed: Dec. 13, 1971 Appl. No.: 207,286

[75] Inventor:

US. Cl. ..323/22 T, 32l/2, 321/27 R, 323/25, 323/DlG. 1

Int. Cl ..G05f l/56 Field of Search ..321/2, 27 R; 323/8, 323/17, 22 T,25, 62, DIG. l

References Cited UNITED STATES PATENTS 2/1969 Thornwall ..321/2 11/1965Keller et al. ..321/2 X 3,300,656 l/1967 Meier et a1 ..321/2 UX3,571,697 3/1971 Phillips ..323/l7 3,523,239 8/1970 Heard ...32l/2 X3,569,817 3/1971 Boehringer ..321/2 Primary ExaminerA. D. PellinenAtt0meyEdward J. Norton [57] ABSTRACT A circuit for increasing andregulating the voltage appearing at the input terminals of a powersupply. A plurality of cascaded stages are provided. Each stagecomprises: an inductive energy storage device; a switching device; acontrol device; and a discharge path. Control signals, having aselectable sequential time relation therebetween, are provided to thestages so that energy discharged from adjacent stages is caused tooverlap in time. The amount of overlap is adjustable and is dependentupon the sequential time relation between the control signals which isselected.

7 Claims, 8 Drawing Figures 10 m VIN Fig 3A Fig. 38

Fig 3C Fig. 30

Fig. 3E

Fig. 3F

PATENTEW- 3.736.496

SHEET1|0F2 19 gm F lg. 1. 22 l0 D I 23 VIN F 14 32 Q y 34 lg D z 40AMPLIFIER 37 V 25 V 39- 68 69 7 0 as VREF 1 1 n A 9. 1 2 a 4.sTAcE-2;--\ g '--smoE-4 STAGE-1;? ,\'\X\STAGE-1 MI AVERAGE 1 b2 b3 b4 b1 1 1 l I I, I 1 b1 b2 b5 b4 b1 M AVERAGE T|ME ENERGY PUMP VOLTAGEREGULATOR This invention relates generally to power supplies and moreparticularly to a regulating power supply having the capability ofincreasing the voltage level appearing at the supply input terminalswhile regulating the voltage at a predetermined level at the outputterminals of the supply.

There are several types of voltage regulators in the prior art that canreduce an input voltage level and maintain the output voltage at arelatively constant level. The latter types of regulators include seriesand shunt power dissipating types, magnetic regulators and duty cyclecontrolled switching regulators with constant or variable operatingfrequencies. The previously mentioned regulators do not generally havethe ability to provide a regulated output voltage whose level is higherthan the input voltage level. Thus, the present invention has beentermed Energy Pump Voltage Regulator.

A device capable of increasing voltage levels as well as performingregulation is extremely useful in extending the life of a primary wet ordry battery, solar cell or any variable power source. An energy pumpregulator, of the type to be described more fully herein, has theability to raise and regulate the voltage from a 6 or 12 volt D. C.battery to, say for example, 28 volts or higher. Should the batteryvoltage drop below its minimum required level, the energy pump regulatorwill increase the output voltage level of the battery to the levelrequired by the working equipment. As a result the energy remaining inthe battery will still be useful. Therefore, the energy pump regulatorwill extend the useful life of a battery such as that found, forexample, in an automobile.

In accordance with the present invention an energy pump circuit isprovided wherein an inductive energy storage means is allowed to storeenergy at selected times while the peak energy level stored in thestorage device is controlled by a variable impedance device. Thevariable impedance device is controlled by a signal related to thesignal appearing across the output terminals. A discharge path isprovided between the energy storage means and at least one outputterminal.

Also, in accordance with the present invention a circuit is providedwherein a plurality of stages are connected between at least one inputterminal and one output terminal. Each stage in the cascaded arrangementcomprises: an energy storage means; a switching device coupled to thestorage means; and a discharge path coupling the energy storage means toone of the output terminals. There is also provided a signal generatingmeans for supplying control signals to each of the switching devices inorder to control the transfer of energy from each of the stages to theoutput terminal.

An energy pump of the last mentioned type permits an overlap inoperation of adjacent-stages by the manner in which the control signalsare applied to the various stages. Overlapping operation of the stagesincreases the power capability of the circuit and increases the averageoutput current and also results in a decrease in the size of storagecapacitors, if required, and reduces the output ripple voltage.

In the Figures:

FIG. 1 is a diagram of an embodiment of a single stage energy pumpregulator according to the present invention;

FIG. 2 is a diagram of an embodiment of a four stage energy pumpregulator according to the present invention; and

FIGS. 3A 3F are waveforms helpful to the explanation of the operation ofthe energy pump regulator shown in FIG. 2.

Referring now to FIG. 1, a source of unregulated D. C. voltage (notshown) supplies a signal V which is applied to a pair of input terminals10 and 11, with the positive polarity being applied to terminal 10, andthe negative polarity being applied to terminal 11. An input circuitcapacitor 12 is connected directly across the input terminals 10 and 11.

Input terminal 10 is also connected to one end of the primary winding 13of transformer T The other end of the primary winding 13 is connected tothe collector electrode 14 of transistor 0 Transistor 0, also has a baseelectrode 15 and an emitter electrode 16.

The base electrode 15 is connected to the cathode electrode 17 of asilicon controlled rectifier SCR,. The anode electrode 18 of SCR, isconnected to one end of the secondary winding 19 of transformer T Aresistor 20 is connected between the gate electrode 21 and the cathodeelectrode 17 of SCR The other end of the secondary winding 19 oftransformer T is connected to the cathode electrode 22 of diode D Theanode electrode 23 of diode D is connected through a resistor 24 to theemitter electrode 25 of transistor Q Transistor 0,, has a base electrode26 and a collector electrode 27.

The collector electrode 27 is connected to the cathode electrode 28 ofdiode D The anode electrode 29 of diode D is connected to the emitterelectrode 16 of transistor 0,. The junction between the anode electrode29 and the emitter electrode 16 is also electri cally connected to theinput terminal 11.

A diode D has its anode electrode 30 connected to the junction pointbetween the collector electrode 14 and the primary winding 13 oftransformer T The cathode electrode 31 of diode D, is connected to oneoutput terminal 32. The load (not shown) to be supplied with the outputvoltage, V,,,,,, may be placed across the output terminals 32 and 33.Output terminal 33 is also electrically connected to the anode electrode29 of diode D,,.

An output filter capacitor 34 is placed across the output terminals 32and 33. Also connected across the output terminals 32 and 33 is avoltage divider network comprising the serial combination of resistor35, potentiometer R, and resistor 36.

The center arm of potentiometer R, is electrically connected to inputterminal 37 of error amplifier 38. A reference signal, V from areference source, (not shown) is suppliedto another input terminal 39 ofamplifier 38. The output terminal 40 of amplifier 38 is connected to thebase electrode 26 of transistor Q The operation of the energy pumpregulator of FIG. 1 is as follows. A positive pulse A is applied to thegate electrode 21 of SCR from a source (not shown) via line 41. Pulse Atriggers the stage into operation.

When SCR is triggered into conduction by the application of pulse A,transistor Q begins to conduct. Transistor Q collector current starts toflow from the positive input terminal 10 through the primary winding 13of transformer T and the collector to emitter path of transistor 0 Thecurrent, rising in magnitude, through the primary winding 13 oftransformer T induces a voltage in the secondary winding 19 oftransformer T The base current supplied to transistor Q will be limitedby the magnitude of the induced voltage in the secondary winding 19 oftransformer T and by the impedance represented by transistor 0,

A regenerative situation has been initiated whereby the forward bias andthe collector current related to transistor Q continue to increase untiltransistor Q reaches a saturated condition of operation.

When transistor Q saturates, the magnetic field created by thepreviously increasing collector current of transistor Q through theprimary winding 13, will suddenly collapse. The induced voltage in thesecondary winding 19 will reverse polarity thereby reverse biasing SCRand cutting-off transistor 0,. The energy stored in the inductancerepresented by the primary winding 13 is now supplied to the outputterminal 32 via the discharge path including the diode D,,.

Upon completion of the discharge of energy from the primary winding 13of transformer T SCR will once again be forward biased by virtue of thevoltage induced in the secondary winding 19. However, the initiation ofenergy storage in the primary winding will not occur until such time asanother pulse is applied to the gate electrode 21 of SCR The transistor0,, acts as a variable impedance device whose impedance is controlled bythe amount of base drive supplied from the output terminal 40 of erroramplifier 38. Error amplifier 38, which may for example, be in the formof a balanced or unbalanced difference amplifier, provides a signal atamplifier output terminal 40 which is related to the signal appearingbetween output terminals 32 and 33.

The application of pulses to the gate electrode 21 of SCR, willdetermine and control the time between the initiations of the energystorage cycle in the primary winding of transformer T Thus the circuitshown in FIG. 1 allows two degrees of freedom in providing a regulatedoutput voltage across terminals 32 and 33, namely, (a) control over theimpedance of transistor 0,, and thus the control over the peak chargingcurrent flowing through the primary winding of transformer T and (b)control over the initiation of the energy storage cycle.

Moreover, the arrangement of FIG. 1 lends itself to a cascading ofstages where overlap operation of individual stages is made possible.The cascade arrangement is shown in FIG. 2, where elements and terminalscommon to FIG. 1 have been given the same identifying designations as inFIG. 1.

In FIG. 2 each of the blocks designated 50, 51, 52 and 53, correspondingto stages 1 4 of the cascade arrangement, contain the circuitrydescribed in conjunction with FIG. 1.

Input terminal is electrically connected to one end of each primarywinding via lines 54 57. Each of stages 1 4 has a connection from therespective emitter electrodes of their transistor 0, to the common linebetween input terminal 11 and output terminal 33 via lines 58 61. Theemitter electrode 25 of transistor 0,, is connected, through resistor 24to the anode electrode of the D diode in each of stages 1 4 via lines 62-65 respectively.

The discharge paths for each of the stages 1 4 are shown outside of theblocks 50 53. Diodes D D D and D are in the respective discharge pathsfor stages 1 4. i

' In addition to the connections just mentioned for cascading stages 14, there is shown in FIG. 2 a pulse se- 'quence generator 66 which isdriven from a clock source designated as variable frequency oscillator67.

The function of the pulse sequence generator 66 is to accept the clocksignal or pulse train from the oscillator 67 and to sequentially providea pulse to each of the generator output terminals 68, 69, 70 and 71.Terminals 68-71 are electrically connected to the gate electrodes of theSCRs in stages 1 4 respectively. Therefore, the gate electrodes of theSCRs in stages 1 4 are supplied by pulses which have a known orpredetermined sequential relationship with respect to each other.

As the frequency of oscillator 67 changes, manually or automatically,the time spacing between the pulses at terminals 68 71 will change. Inthis manner one may control the sequential initiation of the operationof stages 1 4, that is, the relative times at which the operation ofeach stage will be started.

There are several ways to implement the structure of the pulse generator66. One convenient approach is to utilize a ring counter with fouroutput taps. This latter approach is illustrative only and not limitingin the type of structure which may be used to perform the function ofthe oscillator 67 and the ring counter 66.

The operation of the multistage energy pump regulator may be betterunderstood with reference to the waveforms shown in FIGS. 3A F.

FIG. 3A shows the time relationship between the pulses appearing atterminals 68 71 and delivered to the gate electrodes of the SCRs instages 1 4 respectively.

FIG. 3B shows the collector current waveform for the Q transistor foreach of the stages 1 4 (without addition). The dashed line representsthe charging current for the primary winding for each stage and thesolid line represents the discharge current which flows to the loadterminal 32.

FIGS. 3A and 3B taken together demonstrate the sequential operation ofstages 1 4 and also demonstrates how the discharging currents are madeto overlap.

FIG. 3C shows the output current waveform and demonstrates the currentadding capability of the circuit resulting from the overlap operation.

FIG. 3D shows how a decreased frequency clock signal from the oscillator67 spreads out the time between pulses appearing on lines 68 71 ascompared to th time spacing of FIG. 3A.

FIG. 3E shows the decrease in overlap operation as a result of thedecrease in frequency of the signal from the oscillator 67.

FIG. 3F shows how the average current delivered to the output terminal32 is decreased as a result of the decrease in frequency of theoscillator 67.

Returning to the circuit of FIG. 2, if desired, a useful addition to thecircuit may include a connection from the output terminal 40 of theerror amplifier 38 to the frequency control portion of the oscillator67. In this manner, the change in frequency of the oscillator whichresults in a change in overlap operation, leading to a change in outputcurrent delivered to terminal 32, would be made automatically dependentupon the signal appearing across the output terminals. Care must betaken to ensure that this feedback loop is stable in order to avoidundesirable oscillation.

A four stage energy pump regulator circuit has been built and hassuccessfully provided a 32 volt D.C. regulated output voltage for aninput voltage range of 17-30 volts D.C.

Although a four stage energy pump regulator has been described as anembodiment of the invention, many more stages may be employed for aparticular application. The four stage circuit is described only as anillustration of a multistage energy pump regulator.

I claim:

1. An energy pump voltage regulator comprising:

a pair of input terminals adapted for connection to a source ofpotential, said source being capable of providing a range of potentials;

a pair of output terminals adapted for connection to a load;

a plurality of cascade connected stages coupled between at least one ofsaid input terminals and at least one of said output terminals, eachstage comprising:

a. an inductive energy storage means having first and second terminals,the first terminal of said storage means being connected in circuit withone of said input terminals;

b. a switching device having first and second main electrodes and acontrol electrode, the second terminal of said storage means beingconnected in circuit with the first main electrode of said switchingdevice;

0. a control device having first and second main electrodes and acontrol electrode, at least one main electrode of said control devicebeing connected to the control electrode of said switching device; and

d. a discharge path, including a unidirectional semiconductor deviceconnecting the second terminal of said inductive energy storage means toone of said output terminals;

control signal generating means for supplying a plurality of controlsignals, said control signals having a selectable sequential timerelation therebetween;

means for coupling said control signals to a corresponding one of saidcontrol electrodes of said control device in each of said cascadedstages;

each of said cascaded stages being responsive to said control signals todischarge energy over said discharge paths to said one output terminal,said selectable sequential time relation causing an overlap in time ofthe energy discharged from adjacent ones of said cascaded stages to saidone output terminal, the amount of said overlap being determined by theselectable sequential time relation between the control signals;

means for generating an error signal related to the signal appearingacross said output terminals; and

means responsive to said error signal and connected in circuit with thesecond main electrode of said switching devices, said storage means andthe second main electrode of said control devices for controlling themagnitude of the energy stored in each of said inductive storage means;

said circuit being capable of providing a regulated output voltageacross said output terminals for the range of potential supplied by saidsource.

2. The circuit according to claim 1 wherein said inductive storage meanscomprises at least one winding of a transformer and said switchingdevice comprises a transistor and further wherein said control devicecomprises a thyristor.

3. The circuit according to claim 2 further comprising a capacitorconnected across said pair of output terminals.

4. The circuit comprising:

first and second input terminals adapted for connection to a source ofpotential a transformer having first and second windings, one end of thefirst winding being connected in circuit with the first input terminal;

a switching device having first and second main electrodes and a controlelectrode, the first main electrode being connected in circuit with theother end of the first winding of said transformer;

a control means, having two main electrodes and a control electrode, onemain electrode of the control means being connected to the controlelectrode of the switching device, the other main electrode of thecontrol means being connected to one end of the second winding of thetransformer, said control means being adapted for selectivelycontrolling the initiation of the conduction of current through saidswitching device and thereby selectively controlling the initiation ofthe transfer of energy from said source to the first winding of thetransformer;

first and second output terminals adapted for connection to a load, thesecond input terminal being connected to the second output terminal;

a variable impedance device connected in circuit with the second mainelectrode of said switching device and the other end of the secondwinding of the transformer;

feedback means adapted for coupling a signal related to the signalappearing between said output terminals to said variable impedancedevice, and for controlling the impedance of said impedance device; and

means connected in circuit between the first main electrode of saidswitching device and the first output terminal for providing a dischargepath for energy stored in the first winding of the transformer.

5. The circuit according to claim 4 wherein said switching devicecomprises a transistor having a collector, an emitter and a baseelectrode and wherein said control means includes a thyristor having twomain electrodes connected in series with said base electrode and a gateelectrode adapted for connection to a source of selectively generatedsignals.

6. The circuit according to claim 4 further comprising a capacitiveenergy storage means connected in shunt circuit with said outputterminals.

7. The circuit according to claim 6 further including a diode connectedin said discharge path in a direction to transfer energy from the firstwinding of the transformer to the first output terminal.

t l t

1. An energy pump voltage regulator comprising: a pair of inputterminals adapted for connection to a source of potential, said sourcebeing capable of providing a range of potentials; a pair of outputTerminals adapted for connection to a load; a plurality of cascadeconnected stages coupled between at least one of said input terminalsand at least one of said output terminals, each stage comprising: a. aninductive energy storage means having first and second terminals, thefirst terminal of said storage means being connected in circuit with oneof said input terminals; b. a switching device having first and secondmain electrodes and a control electrode, the second terminal of saidstorage means being connected in circuit with the first main electrodeof said switching device; c. a control device having first and secondmain electrodes and a control electrode, at least one main electrode ofsaid control device being connected to the control electrode of saidswitching device; and d. a discharge path, including a unidirectionalsemiconductor device connecting the second terminal of said inductiveenergy storage means to one of said output terminals; control signalgenerating means for supplying a plurality of control signals, saidcontrol signals having a selectable sequential time relationtherebetween; means for coupling said control signals to a correspondingone of said control electrodes of said control device in each of saidcascaded stages; each of said cascaded stages being responsive to saidcontrol signals to discharge energy over said discharge paths to saidone output terminal, said selectable sequential time relation causing anoverlap in time of the energy discharged from adjacent ones of saidcascaded stages to said one output terminal, the amount of said overlapbeing determined by the selectable sequential time relation between thecontrol signals; means for generating an error signal related to thesignal appearing across said output terminals; and means responsive tosaid error signal and connected in circuit with the second mainelectrode of said switching devices, said storage means and the secondmain electrode of said control devices for controlling the magnitude ofthe energy stored in each of said inductive storage means; said circuitbeing capable of providing a regulated output voltage across said outputterminals for the range of potential supplied by said source.
 2. Thecircuit according to claim 1 wherein said inductive storage meanscomprises at least one winding of a transformer and said switchingdevice comprises a transistor and further wherein said control devicecomprises a thyristor.
 3. The circuit according to claim 2 furthercomprising a capacitor connected across said pair of output terminals.4. The circuit comprising: first and second input terminals adapted forconnection to a source of potential a transformer having first andsecond windings, one end of the first winding being connected in circuitwith the first input terminal; a switching device having first andsecond main electrodes and a control electrode, the first main electrodebeing connected in circuit with the other end of the first winding ofsaid transformer; a control means, having two main electrodes and acontrol electrode, one main electrode of the control means beingconnected to the control electrode of the switching device, the othermain electrode of the control means being connected to one end of thesecond winding of the transformer, said control means being adapted forselectively controlling the initiation of the conduction of currentthrough said switching device and thereby selectively controlling theinitiation of the transfer of energy from said source to the firstwinding of the transformer; first and second output terminals adaptedfor connection to a load, the second input terminal being connected tothe second output terminal; a variable impedance device connected incircuit with the second main electrode of said switching device and theother end of the second winding of the transformer; feedback meansadapted for coupling a signal related to the sIgnal appearing betweensaid output terminals to said variable impedance device, and forcontrolling the impedance of said impedance device; and means connectedin circuit between the first main electrode of said switching device andthe first output terminal for providing a discharge path for energystored in the first winding of the transformer.
 5. The circuit accordingto claim 4 wherein said switching device comprises a transistor having acollector, an emitter and a base electrode and wherein said controlmeans includes a thyristor having two main electrodes connected inseries with said base electrode and a gate electrode adapted forconnection to a source of selectively generated signals.
 6. The circuitaccording to claim 4 further comprising a capacitive energy storagemeans connected in shunt circuit with said output terminals.
 7. Thecircuit according to claim 6 further including a diode connected in saiddischarge path in a direction to transfer energy from the first windingof the transformer to the first output terminal.